add int32 and string types to alignedbuff (#195)

alignedbuff/alignedbuff.go

@@ -118,6 +118,39 @@ func (a *AlignedBuff) Uint64() (uint64, error) {
 	return v, nil
 }
 
+// Int32 unmarshals an int32 in native endianess and alignment. It returns
+// ErrEOF when trying to read beyond the payload.
+func (a *AlignedBuff) Int32() (int32, error) {
+	if err := a.alignCheckedRead(int32AlignMask); err != nil {
+		return 0, err
+	}
+	v := binaryutil.Int32(a.data[a.pos : a.pos+4])
+	a.pos += 4
+	return v, nil
+}
+
+// String unmarshals a null terminated string
+func (a *AlignedBuff) String() (string, error) {
+	len := 0
+	for {
+		if a.data[a.pos+len] == 0x00 {
+			break
+		}
+		len++
+	}
+
+	v := binaryutil.String(a.data[a.pos : a.pos+len])
+	a.pos += len
+	return v, nil
+}
+
+// Unmarshals a string of a given length (for non-null terminated strings)
+func (a *AlignedBuff) StringWithLength(len int) (string, error) {
+	v := binaryutil.String(a.data[a.pos : a.pos+len])
+	a.pos += len
+	return v, nil
+}
+
 // Uint unmarshals an uint in native endianess and alignment for the C "unsigned
 // int" type. It returns ErrEOF when trying to read beyond the payload. Please
 // note that on 64bit platforms, the size and alignment of C's and Go's unsigned
@@ -190,6 +223,19 @@ func (a *AlignedBuff) PutUint64(v uint64) {
 	a.pos += 8
 }
 
+// PutInt32 marshals an int32 in native endianess and alignment.
+func (a *AlignedBuff) PutInt32(v int32) {
+	a.alignWrite(int32AlignMask)
+	a.data = append(a.data, binaryutil.PutInt32(v)...)
+	a.pos += 4
+}
+
+// PutString marshals a string.
+func (a *AlignedBuff) PutString(v string) {
+	a.data = append(a.data, binaryutil.PutString(v)...)
+	a.pos += len(v)
+}
+
 // PutUint marshals an uint in native endianess and alignment for the C
 // "unsigned int" type. Please note that on 64bit platforms, the size and
 // alignment of C's and Go's unsigned integer data types differ, so we
@@ -236,5 +282,7 @@ var uint32AlignMask = int(unsafe.Alignof(uint32(0)) - 1)
 var uint64AlignMask = int(unsafe.Alignof(uint64(0)) - 1)
 var padding = bytes.Repeat([]byte{0}, uint64AlignMask)
 
+var int32AlignMask = int(unsafe.Alignof(int32(0)) - 1)
+
 // And this even worse.
 var uintSize = unsafe.Sizeof(uint32(0))

alignedbuff/alignedbuff_test.go

@@ -20,6 +20,9 @@ func TestAlignmentData(t *testing.T) {
 	if uintSize == 0 {
 		t.Fatal("zero uint size")
 	}
+	if int32AlignMask == 0 {
+		t.Fatal("zero uint32 alignment mask")
+	}
 }
 
 func TestAlignedBuff8(t *testing.T) {
@@ -202,3 +205,114 @@ func TestAlignedUint(t *testing.T) {
 		t.Fatalf("sentinel read failed")
 	}
 }
+
+func TestAlignedBuffInt32(t *testing.T) {
+	b0 := New()
+	b0.PutUint8(0x42)
+	b0.PutInt32(0x12345678)
+	b0.PutInt32(0x01cecafe)
+
+	b := NewWithData(b0.data)
+
+	if len(b0.Data()) != 4*4 {
+		t.Fatalf("alignment padding failed")
+	}
+
+	v, err := b.Uint8()
+	if v != 0x42 || err != nil {
+		t.Fatalf("unaligment read failed")
+	}
+	tests := []struct {
+		name string
+		v    int32
+		err  error
+	}{
+		{
+			name: "first read",
+			v:    0x12345678,
+			err:  nil,
+		},
+		{
+			name: "second read",
+			v:    0x01cecafe,
+			err:  nil,
+		},
+		{
+			name: "end of buffer",
+			v:    0,
+			err:  ErrEOF,
+		},
+	}
+
+	for _, tt := range tests {
+		v, err := b.Int32()
+		if v != tt.v || err != tt.err {
+			t.Errorf("expected: %#v %#v, got: %#v, %#v",
+				tt.v, tt.err, v, err)
+		}
+	}
+}
+
+func TestAlignedBuffPutNullTerminatedString(t *testing.T) {
+	b0 := New()
+	b0.PutUint8(0x42)
+	b0.PutString("test" + "\x00")
+
+	b := NewWithData(b0.data)
+
+	v, err := b.Uint8()
+	if v != 0x42 || err != nil {
+		t.Fatalf("unaligment read failed")
+	}
+	tests := []struct {
+		name string
+		v    string
+		err  error
+	}{
+		{
+			name: "first read",
+			v:    "test",
+			err:  nil,
+		},
+	}
+
+	for _, tt := range tests {
+		v, err := b.String()
+		if v != tt.v || err != tt.err {
+			t.Errorf("expected: %#v %#v, got: %#v, %#v",
+				tt.v, tt.err, v, err)
+		}
+	}
+}
+
+func TestAlignedBuffPutString(t *testing.T) {
+	b0 := New()
+	b0.PutUint8(0x42)
+	b0.PutString("test")
+
+	b := NewWithData(b0.data)
+
+	v, err := b.Uint8()
+	if v != 0x42 || err != nil {
+		t.Fatalf("unaligment read failed")
+	}
+	tests := []struct {
+		name string
+		v    string
+		err  error
+	}{
+		{
+			name: "first read",
+			v:    "test",
+			err:  nil,
+		},
+	}
+
+	for _, tt := range tests {
+		v, err := b.StringWithLength(len("test"))
+		if v != tt.v || err != tt.err {
+			t.Errorf("expected: %#v %#v, got: %#v, %#v",
+				tt.v, tt.err, v, err)
+		}
+	}
+}

binaryutil/binaryutil.go

@@ -16,6 +16,7 @@
 package binaryutil
 
 import (
+	"bytes"
 	"encoding/binary"
 	"unsafe"
 )
@@ -102,3 +103,23 @@ func (bigEndian) Uint32(b []byte) uint32 {
 func (bigEndian) Uint64(b []byte) uint64 {
 	return binary.BigEndian.Uint64(b)
 }
+
+// For dealing with types not supported by the encoding/binary interface
+
+func PutInt32(v int32) []byte {
+	buf := make([]byte, 4)
+	*(*int32)(unsafe.Pointer(&buf[0])) = v
+	return buf
+}
+
+func Int32(b []byte) int32 {
+	return *(*int32)(unsafe.Pointer(&b[0]))
+}
+
+func PutString(s string) []byte {
+	return []byte(s)
+}
+
+func String(b []byte) string {
+	return string(bytes.TrimRight(b, "\x00"))
+}

binaryutil/binaryutil_test.go

@@ -107,3 +107,36 @@ func TestBigEndian(t *testing.T) {
 		}
 	}
 }
+
+func TestOtherTypes(t *testing.T) {
+	tests := []struct {
+		name      string
+		expected  []byte
+		expectedv interface{}
+		actual    []byte
+		unmarshal func(b []byte) interface{}
+	}{
+		{
+			name:      "Int32",
+			expected:  []byte{0x78, 0x56, 0x34, 0x12},
+			expectedv: int32(0x12345678),
+			actual:    PutInt32(0x12345678),
+			unmarshal: func(b []byte) interface{} { return Int32(b) },
+		},
+		{
+			name:      "String",
+			expected:  []byte{0x74, 0x65, 0x73, 0x74},
+			expectedv: "test",
+			actual:    PutString("test"),
+			unmarshal: func(b []byte) interface{} { return String(b) },
+		},
+	}
+	for _, tt := range tests {
+		if bytes.Compare(tt.actual, tt.expected) != 0 {
+			t.Errorf("Put%s failure, expected: %#v, got: %#v", tt.name, tt.expected, tt.actual)
+		}
+		if actual := tt.unmarshal(tt.actual); !reflect.DeepEqual(actual, tt.expectedv) {
+			t.Errorf("%s failure, expected: %#v, got: %#v", tt.name, tt.expectedv, actual)
+		}
+	}
+}